1. Field of the Invention
This invention relates to aromatic sulfide polymers. In one aspect, the invention relates to aromatic sulfide polymers suitable for use in conductive applications. In another aspect, the invention relates to high temperature aromatic sulfide polymers. In another aspect, the invention relates to methods for producing aromatic sulfide polymers.
2. Description of the Prior Art
Aromatic sulfide polymers are generally well known for their thermal stability and chemical resistance. Various aromatic sulfide polymers have also proven to be well suited for use as base compounds in conductive applications. In conductive applications, electrical conductivity is imparted to the aromatic sulfide polymer using methods known in the art. Aromatic sulfide polymers are used to manufacture extremely lightweight electrical components such as capacitors, circuit boards, integrated circuits, etc.
Most prior art methods for producing aromatic sulfide polymers require the use of aromatic reactants which have chloronated aromatic nuclei. The need to use chloronated aromatic reactants is disadvantageous due to the difficulty experienced in placing chloro groups in the required reactive positions on the aromatic nucleus.
It is also known that aromatic sulfide polymers having repeating units of the formula: ##STR1## can be produced by reacting benzene, diphenyl sulfide, or thianthrene with sulfur using an aluminum chloride catalyst and a 1,2,4-trichlorobenzene solvent. Benzene, diphenyl sulfide, and thianthrene have the following formulas: ##STR2##
The present invention provides a novel and economical method for producing high temperature aromatic sulfide polymers having repeating units of the formula: ##STR3## which are suitable for use in conductive applications. The production of these polymers by the method of the present invention has heretofore been unknown. In the method of the present invention, aromatic sulfide polymers are produced by reacting diaromatic reactant compounds of the formula: ##STR4## with elemental sulfur in an inert polyhaloaromatic solvent and in the presence of a strong Friedel-Crafts metallic halide catalyst. In all of the formulas provided above, R.sup.1 and R.sup.2 are independently selected from hydrogen and alkyl groups having from about 1 to about 6 carbon atoms and n is 0 or 1.
When the selected diaromatic reactant compound is diphenyl ether, the aromatic sulfide polymer produced according to the method of the present invention is poly(phenoxathiinyl sulfide). Poly(phenoxathiinyl sulfide) is a novel, high temperature aromatic sulfide polymer which has heretofore been unknown. Poly(phenoxathiinyl sulfide) is well suited for use as a base compound in conductive applications.